I spent 5 years doing my PhD research (4 years experiments, and one year writing the manuscript, making the figures and getting it revised and submitted by the supervisor. We submitted the paper (I was the first author) which is rejected with a recommendation for one more experiment, and resubmission. Three colleagues did it, as my scholarship was ended and as I was busy writing the thesis. I was shocked that the supervisor (PI) put one colleague instead of me as a first author, who just carried out this last experiment with help of two other colleagues (were added as co-authors). That colleague was busy doing her own project and did not do that much to my project except for that last experiment and revising the manuscript and giving some comments for correction. I refused the new order, though the paper was sent to the journal. How could I get my first authorship?